I have the same problem, used the search function to look for an answer and found this post. I know the question was asked before, I remember Roger saying WD-40 is not the answer because of the risk of leaving a petroleum based residue that could damage monofilm. Unfortunately, I don&#39;t remember what he recommended.

Hi Del,
Roger likes and uses acetone....very carefully!
Bill Hansen does not like acetone, and suggests lacquer thinner, mineral spirits (paint thinner) and Goo Gone.
I&#39;ll have to try the lacquer thinner, but I&#39;ve always used acetone, and it works great, but don&#39;t get it anywhere near a seam, as it will melt the glue that holds the sail together.
Also, use it very sparingly, just dampen a cloth or paper towel and wipe the number or gooey area quickly.
DO NOT allow acetone to "pool" on your sail as it will quickly eat through the monofilm or x ply scrim.
Hope this helps,

A while back I took all the advertisers&#39; stickers off of one of Kevin&#39;s former sails. It&#39;s a tough job which requires considerable elbow grease. I wouldn&#39;t do it again. The Bic stickers were worse than the Fiberspar. I figured they would make better sail repair material than the tape sold commercially. Goo Gone sold in the states works best as I remember. The sail is still in good shape. I rigged it a couple of days ago. I tried a number of products, including WD-40, but have cleaned all thoroughly off.

For dirty luff tubes Stardrops is good as is Swarfega. (Non-grit one)
Not sure with residue left from stickers . Mer (car polish) is pretty good and even gets rid of some of the misting.(with enougfh elbow grease)
I have used Acetone but very sparingly. White spirits and meths work on some too.(Again be carefull though)
Left a sail in our hot tub (on hottest setting with stardrops in water) Sail waas marginally cleaner but house was full of soap suds. (Well gaerden was)

Just before I started to test some acetone and paint thinner I had to degrease my hands from another project. I used "Goop" to clean my hands, read the label and wondered if it would remove the glue residue. i applied a few drops with a finger in a tiny area and rubbed it in then I quickly wiped it off with a tissue. I noticed that area of the glue wasn&#39;t sticky anymore. Then I rubbed the nonsticky residue with a fingernail and it came off.

I&#39;m now testing leaving some "Goop" on the monofilm of a junked sail overnight. The "Goop" ingredients are "isoparafins, water, fatty acid, surfactants, gylcerine, lanolin, fragrance, preservatives. I&#39;m hoping the "Goop" will turn out to be safe for the monofilm, but I&#39;m also guessing it will require more rubbing work and will be slower than the other solutions already mentioned.